Small update to net/thingsd port, bumping to 4.0.0.
* Refactor code to make more sense about what code is doing what, events-wise
* Fix improper assumptions about how to move sockets to children processes
* Remove default shared port design
* Require UDP bind interface
* Require individual listen ports per thing. Note, the last two update
* change the config grammar.
* Remove multiple subscriptions for clients across things
* Fix so all interfaces are bound to a socket when requested
* Update example config with those changes
* Fix thingsctl and tls to work with the new changes